JP2000343080A - Electrolyzed water production device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To monitor a hypochlorous acid concn. in the produced strongly acidic water without using a color reagent and also to increase its measuring accuracy. SOLUTION: The strongly acidic water and the strongly alkaline water produced at an electrolytic cell 11 are conducted respectively to each individual liq. tank 62 and 63 of an air open type first liq. tank 61, then each liq. is sent to an air open type second liq. tank 67 by suction tubes 64 and 65 and shear pumps 73 and 74, and the liq. is forcively agitated by a stirrer 71 to sufficiently mix both liquids, and the mixture is sent to a flow cell 31 by a suction tube 68 and a shear pump 75. The flow cell 31 is irradiated with a light from a light source 32, and transmitted light is bisected by a beam slitter 33, and one side is conducted to a photocell 36 via an optical filter 34 transmitting near 292 nm wave length and the other side is conducted to a photocell 37 via an optical filter 35 transmitting >=400 nm wave length respectively, and the hypochlorous acid concn. is obtained from their detected output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing electrolyzed water used in the fields of medicine, food industry, agriculture, etc., and more particularly to an apparatus for monitoring the concentration of hypochlorous acid contained in the generated strongly acidic water. About.

[0002]

2. Description of the Related Art An electrolyzed water producing apparatus produces strongly acidic water on the anode side and strongly alkaline water on the cathode side by electrolyzing chlorine-containing water. When the water contains chlorine, the strongly acidic water generated on the anode side contains hypochlorous acid having a sterilizing ability. In particular, the strongly acidic water generated on the anode side when electrolysis is performed by adding sodium chloride, potassium chloride, or the like to water, has several tens of hypochlorous acid.
ppm, low pH (2.5-3.0), high ORP (+
(About 1100 mV), and is known to have a strong bactericidal effect (ORP represents an oxidation-reduction potential).

[0003] In the medical field, the generated strongly acidic water is used for disinfection of hands at hospitals and MR causing nosocomial infections.
It is used as an agent for disinfecting SA and the like, and is used in the food industry for disinfecting and disinfecting kitchen equipment, disinfecting fish in the fishery processing industry, disinfecting O-157, and the like. In the field of agriculture, strongly acidic water obtained by electrolyzing water added with potassium chloride is used to disinfect pathogenic bacteria in house cultivation (melon, vegetables, pears, flowers, etc.) and sterilize rice pulp. There is a movement to reduce the amount of pesticides used and promote environmentally friendly agriculture.

[0004]

However, the conventional electrolyzed water producing apparatus has a problem that there is no means for confirming whether or not strong acid water having a bactericidal effect is actually produced. For this reason, there is a risk that the user may continue to use the strong acid water without knowing it even if the specified strong acid water cannot be obtained due to a failure of the device, etc., because the purpose of use is related to physical safety and hygiene such as sterilization and disinfection. That is important.

The concentration of hypochlorous acid, which is a source of sterilization ability, in the highly acidic water is naturally determined by the properties of tap water and pure water to be used, temperature, pH, amount of strongly acidic water produced per unit time, and the like. It fluctuates, but this is not known to the user. Of course, it is conceivable to prepare a coloring reagent such as ortho-tolidine separately outside the device, mix it with strongly acidic water on the anode side, and measure the concentration by a colorimetric method.・ Management is time-consuming and burdensome in terms of cost, making it impractical.

SUMMARY OF THE INVENTION In view of the above, the present invention provides an electrolytic water production apparatus which monitors the concentration of hypochlorous acid in strongly acidic water without increasing labor and cost and improves the measurement accuracy. The purpose is to:

[0007]

In order to achieve the above object, an electrolyzed water producing apparatus according to the present invention includes two electrodes, and applies a positive / negative voltage to each of the electrodes to obtain a chlorinated water. An electrolytic cell capable of electrolyzing water, a two-tank first open-to-atmosphere type liquid tank in which water respectively guided from both electrode sides is introduced into each of the separated tanks, A first and a second liquid sending means for independently sending water in each tank of the open-to-atmosphere type liquid tank, and a second means for storing these sent waters and mixing them by forcible stirring. An open-to-atmosphere type liquid tank, a third liquid-feeding means for feeding the mixed liquid of the second air-to-atmosphere type liquid tank at a predetermined flow rate, and a mixed liquid sent by the third liquid-feeding means Measuring means for measuring the light absorption intensity substantially in the wavelength range of 260 nm to 330 nm. Erareru it has become a feature.

Further, means for arbitrarily stopping the electrolysis by not applying a voltage to each electrode in the electrolytic cell, and measuring the light absorption intensity of the light measured by the measuring means when the electrolysis is stopped. Means may be provided for correcting the measured value of light absorption intensity during electrolysis in the electrolytic cell.

Chlorine is in an equilibrium state between chlorine (molecule) and hypochlorous acid (HClO) as shown in the following chemical formula 1 at a pH of 5 or less, and as shown in the following chemical formula 2 at a pH of 5 or more.
As shown in the figure, there is an equilibrium between hypochlorous acid and negative hypochlorite ions.

Embedded image

Embedded image On the other hand, hypochlorite ion exhibits characteristic absorption that causes a peak in a light absorption spectrum near a wavelength of 292 nm.

Therefore, even if the strongly acidic water generated on the anode side contains hypochlorous acid, it does not exist as hypochlorite ion because of its strong acidity. Does not cause light absorption. On the other hand, if strong alkaline water generated on the cathode side is added,
To increase the dissociation of hypochlorous acid into hypochlorite ions.

[0011] Therefore, a part of the strongly acidic water generated on the anode side and a part of the strongly alkaline water generated on the cathode side are guided and mixed.
If the absorption intensity of light in the range of m to 330 nm is measured, the concentration of hypochlorite ion having characteristic absorption peaking at a wavelength of around 292 nm, that is, hypochlorite in strong acid water before mixing, Acid concentration can be measured. Since the concentration of hypochlorous acid contained in the strongly acidic water generated on the anode side is measured using the strong alkaline water generated on the cathode side, a coloring reagent is not required, which reduces labor and cost. Can be reduced.

The generated acidic water contains chlorine gas and oxygen gas, and the alkaline water contains hydrogen gas, and both are a gas-liquid mixture containing a large amount of gas. Further, tap water or the like to be measured contains dissolved calcium carbonate, magnesium carbonate, salts of silica, and the like, which precipitate as a result of electrolysis and float in the generated alkaline water. When measuring the light absorption intensity of a liquid mixture of the acidic water and the alkaline water, if bubbles exist in the liquid, the amount of transmitted light changes due to light scattering, and a correct measurement result cannot be obtained.

However, bubbles vary in size from those having a maximum diameter of up to 10 mm to those having a diameter of 1 mm or less, and have a variation in size.

Therefore, the above-mentioned problem is effectively solved by a two-stage process using the first liquid tank and the second liquid tank. That is, a two-tank type open-to-the-atmosphere type liquid tank is used as the first liquid tank, and the generated acidic water and the generated alkaline water are respectively introduced into the separated tanks, and then the liquids are introduced. Upon removal, large bubbles are removed by venting to the atmosphere.

[0015] In the second step, each of the extracted liquids is introduced into a second open-to-atmosphere type liquid tank and stored. In the second open-to-atmosphere liquid tank, the two liquids are sufficiently mixed by forced stirring. This mixed liquid is sent by the third liquid sending means and guided to the measuring means. The first, second, and third liquid feeding means are independent of each other, and the respective flow rates can be independently changed. Therefore, as a result of long-term use, even if the flow path resistance changes due to the adhesion of dirt or the like in the flow path, the strong acid water and the strong alkaline water guided to the second liquid tank correspondingly change. The flow rate ratio can be made constant, and the flow rate of the mixture guided to the measuring means can be made a predetermined value.

The light absorption intensity of water (tap water) itself, which is a raw material for electrolysis, not only varies from region to region, but also varies insignificantly depending on the season and weather (so-called water quality change). Especially after rain, the turbidity of water quality is reflected, and an apparent increase in concentration is observed. Therefore, means for arbitrarily stopping the electrolysis is provided, and the measurement is performed during the stop in the same manner as in the electrolysis. In the measurement at the time of stopping the electrolysis, as in the electrolysis, water guided from both electrode sides of the electrolytic cell was once introduced into each tank of the first two-tank open-to-atmosphere liquid tank. Thereafter, the liquid is guided to the second open-to-atmosphere type liquid tank by the first and second liquid sending means, stirred therein, guided to the measuring means by the third liquid sending means, and has a wavelength of 260 nm.
The light absorption intensity in the range of ３３０330 nm will be measured. In other words, at this time, the water introduced into the first electrolytic cell was measured without electrolysis as it was, and the measured value of the light absorption intensity of the raw water itself such as introduced tap water (this is called a blank value) To) can be obtained.
Therefore, when the quality of the raw water or the like fluctuates due to the season or the like, the fluctuation is measured as a blank value, and the fluctuation can be corrected. That is,
By correcting the measured value of the light absorption intensity at the time of electrolysis with the above blank value, the concentration of hypochlorous acid in the strongly acidic water obtained by the electrolysis is not affected by fluctuations in water quality, etc. Can be measured.

[0017]

Next, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the electrolyzed water producing apparatus according to the present invention includes an electrolyzed water generating unit 10, a measuring unit 30, and a mixing unit 60 for sending a mixed liquid for measurement to the measuring unit 30. The electrolyzed water generation unit 10 includes an electrolyzer 11.
In this case, about 2 sodium chloride is supplied through the valve 16.
Tap water to which 0 mmol is added is introduced (this raw water supply system will be specifically described later with reference to FIG. 2). The anode 12 and the cathode 1 disposed with the diaphragm 15 interposed therebetween
3, a DC voltage source 14 is connected. The strongly acidic water generated on the side of the anode 12 is taken out from the strongly acidic water outlet 17, and the strongly alkaline water generated on the side of the cathode 13 is taken out from the strongly alkaline water outlet 18. Used for Further, the outlets 17 and 18 are provided with branches for measurement so that a part of strong acid water and a part of strong alkaline water are taken out for measurement through valves 21 and 22, respectively. (Note that the polarity of the applied voltage from the DC voltage source 14 to the electrodes 12 and 13 is periodically switched as described later, so that the anode / cathode may be changed at a certain point in time. When the polarity is switched, the relationship between the anode and the cathode and the relationship between the strongly acidic water and the strongly alkaline water are reversed.)

The strongly acidic water and the strong alkaline water sampled in this manner are supplied to the liquid tank 62 of the first liquid tank 61 of the mixing section 60,
After being led to each of 63, it is led to the second liquid tank 67 and mixed. The first and second liquid tanks 61 and 67 are both liquid tanks that are open to the atmosphere, and are made of, for example, a vinyl chloride-based material because of their resistance to acidic water.

The first liquid tank 61 is an independent liquid tank 6
It is a two-tank type having two, 63, and each of the tanks 62, 63 has a large-area air opening (upper surface). Liquid tanks 62, 63
Are provided with an inlet and an outlet, and the strong acid water and the strong alkaline water introduced from the inlet are supplied to these tanks 62,
Once stored in 63. Each of the liquid tanks 62 and 63 may be, for example, a square pillar having a bottom surface of 100 mm square.

The strongly acidic water generated in the electrolytic cell 11 contains chlorine gas and oxygen gas, and the strongly alkaline water contains hydrogen gas, and both are a gas-liquid mixture containing a large amount of gas. Bubbles in these liquids vary in size from as large as 10 mm in maximum diameter to as small as 1 mm or less.

Such strongly acidic water and strongly alkaline water are led out of the electrolytic cell 11 at a pressure close to that of raw water such as tap water, but the liquid tanks 62 and 63 having a wide-area air opening on the upper surface.
Each gas is temporarily accumulated and returned to the atmospheric pressure, so that a large bubble having a diameter of about 2 mm to 10 mm immediately collapses, and the gas trapped in the bubble is released to the surrounding atmosphere.

Therefore, the suction tubes 64 and 65 are connected to the liquid tank 6.
By inserting the supernatant into each of 2, 63 and sucking the supernatant, strong acid water and strong alkali water from which large bubbles have been removed can be taken out. This suction tube 64,
Numeral 65 is made of a vinyl chloride tube, a Teflon tube, or the like. For example, by using independent ironing pumps 73 and 74 as shown in FIG. It is led to the tank 67. The second liquid tank 67 is an open-to-atmosphere liquid tank having an open upper surface, like the first liquid tank 61.

The distal end of a suction tube 68 made of vinyl chloride or Teflon provided with a filter 69 is inserted into the second liquid tank 67. This suction tube 6
The liquid in 8 is sucked by an ironing pump 75 at a predetermined flow rate. The liquid mixture thus sucked is sent to the flow cell 31 of the optical measuring unit 30 at a predetermined flow rate.

The second liquid tank 67 has a stirring motor 7.
The stirrer 71 is rotated by the stirrer 2 so that the introduced strongly acidic water and strongly alkaline water are forcibly stirred and mixed. for that reason,
The strongly acidic water and the strongly alkaline water are sufficiently mixed. The stirrer 71 can be formed by attaching a flat propeller to the tip of the rotating shaft of the motor 72, and is located between the tips of the suction tubes 64 and 65 and the tip of the suction tube 68. To be.

The strong acid water and the strong alkali water sucked from the first liquid tank 61 contain a large number of fine bubbles each having a diameter of 1 mm or less, but the bonding is repeated while passing through the suction tubes 64 and 65. It grows into bubbles with a diameter of about 1-2 mm. The mixture contains these bubbles,
By being introduced into the second liquid tank 67, the bubbles are radiated into the atmosphere. Such a mixed liquid is sucked by the suction tube 68, so that the mixed liquid from which relatively small bubbles have been removed can be sent to the measuring unit 30.

Here, since the filter 69 having a fine mesh is attached to the tip of the suction tube 68, it is possible to reliably prevent air bubbles, precipitated salts and the like from being sucked into the suction tube 68. That is, the second liquid tank 67
The air bubbles having a diameter of about 1 to 2 mm remaining in the mixed liquid cannot be penetrated through the filter 69 and are diffused into the atmosphere. Examples of the filter 69 include resins such as Teflon and nylon, and cloths such as cotton cloth.
Alternatively, papers such as filter paper can be used.

As described above, since bubbles and the like vary greatly in dimensions and are various, it is difficult to remove them by one treatment, but as described above, the first and second liquid tanks 61,
The two-step process using the 67 makes it possible to reliably remove the resin. If sent to the flow cell 31 without sufficient removal of bubbles and precipitated salts, the light will be scattered by the bubbles, making it impossible to accurately measure the amount of transmitted light, and the deposited salts will adhere to the wall surface of the flow cell 31. In the long term, the amount of transmitted light gradually decreases, causing drift and sensitivity reduction, resulting in a problem that measurement accuracy is deteriorated, but bubbles and precipitated salts are sufficiently removed. Therefore, this problem can be solved and measurement accuracy can be improved.

The ironing pumps 73, 74 and 75 for sending the strongly acidic water, the strongly alkaline water and the mixed solution are independent of each other, and the flow rates and the like can be adjusted independently. That is, an arbitrary flow rate can be set by arbitrarily changing the rotation speed and the tube diameter. Therefore, even when the flow path resistance changes due to the influence of dirt or the like in the flow path due to long-term use, the mixing ratio between the strongly acidic water and the strongly alkaline water can be kept constant.

The measuring section 30 is provided with a flow cell 31 made of quartz glass or the like to which a mixed liquid is sent, a light source 32 and photocells 36 and 37 arranged so as to sandwich the flow cell 31. The light source 32 is composed of, for example, a xenon flash lamp or a deuterium lamp. This light passes through the flow cell 31, is split into two by a beam splitter 33 such as a quartz plate, and is guided to photocells 36 and 37. Photocell 3
Optical filters 34 and 35 are attached to 6 and 37, respectively. One optical filter 34 has a main transmission wavelength 292
The other optical filter 35
Is composed of a bandpass filter (or a sharp cut filter) that transmits light in a long wavelength range of 400 nm or more.

Each of the photocells 36 and 37 is composed of, for example, a Si photocell or the like, and a detection signal (electric signal) is sent to a photometric electric circuit (not shown) to be converted into an absorbance. The calculation for the calculation and the conversion to the hypochlorous acid concentration are performed. That is, the absorbance for light having a wavelength of 292 nm and 400 n
The difference from the absorbance for light having a long wavelength of m or more is determined. This absorbance difference is converted into a hypochlorous acid concentration by multiplying by a correction factor corresponding to the mixture ratio, and the concentration is displayed on a display device or the like. The concentration data is output to an external device such as a controller of the electrolyzed water generator 10 or a printer as necessary.

FIG. 2 shows a more specific form of such an electrolyzed water producing apparatus. The measurement unit 30 and the mixing unit 60 are formed in a separate housing 76 from the electrolytic water generation unit 10. A first liquid tank 61 having individual liquid tanks 62 and 63 and a second liquid tank 67 are arranged below the housing, and ironing pumps 73, 74 and 75 are placed directly above them. Above the mixing section 60, the measuring section 30 is arranged. The measurement unit 30 is formed together with a main board 78 on which a measurement electric circuit, a control circuit, and the like are formed, and is entirely covered with a light shielding cover 77. The hypochlorous acid concentration data obtained from the main board 78 is sent to the electrolyzed water generator 10 and used for control. The electrolyzed water generator 10
The housing 76 and the housing 76 may be configured to be separated via a partition plate. The measuring unit 30 and the mixing unit 60 may be independent units, respectively, or may be entirely housed in one housing with a partition plate interposed therebetween.

Tap water is supplied to the electrolyzed water generator 10. More specifically, after mixing with saturated salt water sent from a salt water tank 82 by a liquid feed pump 83 in a mixer 84, a valve is provided. It is sent to the electrolytic cell 11 (FIG. 1) via 16. This tap water may be softened through a water softener 81. The valve 6 is, for example, a two-way solenoid valve, and is controlled by a main board 78. Note that a control circuit including a CPU is formed on the main board 78. The on / off of the liquid sending pump 83 for sending the salt water from the salt water tank 82 is also controlled by the control circuit of the main board 78. Further, the electrolyzed water generator 1
Switching of the polarity of the DC voltage source 14 at 0, temporary disconnection of the DC voltage source 14 from the electrodes 12 and 13, etc.
It is controlled by the control circuit of the main board 78.

Next, the principle of measuring the concentration of hypochlorous acid will be described. First, the absorption spectrum of only the strongly acidic water generated on the anode 12 side (without mixing with strongly alkaline water) was measured by a separately prepared absorption spectrometer, and the result shown in FIG. 3 was obtained. . FIG. 4 shows the absorption spectrum of only the strong alkaline water generated on the cathode 13 side measured in the same manner. Further, the absorption spectrum of the mixed water in which the strongly acidic water and the strongly alkaline water were mixed at a mixing ratio of 1: 2 was as shown in FIG.

Here, in the spectrum of FIG. 3, it can be seen that a weak shoulder is observed in the ultraviolet region, but no absorption peak is recognized. In the spectrum of FIG. 4, no characteristic absorption exists in the ultraviolet region. On the other hand, in the above mixed solution, characteristic absorption having a peak near 292 nm is observed as shown in FIG.

Here, it is known that the content ratio of free chlorine changes as shown in FIG. 6 depending on the pH. Since the strongly acidic water at the time of generation has a pH of 2.5 to 3.0, according to FIG. 6, free chlorine mainly exists as hypochlorous acid, and a part thereof is dissolved as chlorine (molecule). (See Chemical Formula 1 above).
This is also shown from the absorption spectrum of strongly acidic water in FIG. That is, hypochlorous acid and chlorine have no characteristic absorption in the ultraviolet region.

On the other hand, hypochlorite ion present at a pH of about 6 to 7 or more (see the above chemical formula 2) has an absorption peak at a wavelength of about 292 nm. To confirm this, antiformin (sodium hypochlorite;
NaClO) aqueous solution was prepared, and the absorption spectrum of the aqueous solution was measured. The result is as shown in FIG. According to this, the absorption peak at around 292 nm in the ultraviolet region was clearly judged by judging that this sample was an aqueous solution of pure antiformin, and the characteristic absorption by hypochlorite ion dissociated from sodium hypochlorite was apparent. it is conceivable that.

Therefore, comparing FIG. 5 with FIG. 7,
It can be seen that there is good agreement including the fact that the absorption peak itself is near 292 nm, except that the spectrum shapes are slightly different (the degree of valley cut around 230-240 nm is different). From this, when strongly acidic water and strongly alkaline water are mixed at a ratio of 1: 2, the pH changes, and as shown in the above chemical formula 2, hypochlorous acid becomes a positive hydrogen ion and a negative hypochlorite ion. It is considered that the hypochlorite ion caused an absorption peak in the mixed water, and as a result, a spectrum as shown in FIG. 5 was observed.

The problem, however, is whether this absorption peak near the wavelength of 292 nm accurately represents the concentration of hypochlorous acid in the strongly acidic water before being mixed with the strongly alkaline water. That is, according to FIG. 6, if the pH of the mixed solution is 10 or less, hypochlorous acid and hypochlorite ions are mixed, and even if the absorption by hypochlorite ions is measured, This is because the concentration of chlorite itself is not measured. On the other hand, if the pH of the mixture is 10 or more, hypochlorous acid is completely dissociated into hypochlorite ions,
Measuring the UV absorbance at 292 nm will give a measured value that exactly corresponds to the chlorite concentration.

Then, the relationship between the mixture ratio of the mixed solution and the pH was measured, and the result as shown in FIG. 8 was obtained. According to this, the pH exceeds 10 at a mixing ratio of about 1: 1.65, and the pH becomes 10.4 at a mixing ratio of 1: 2, and all the hypochlorous acid in the mixed solution is dissociated into hypochlorite ions. It can be seen that the pH is in a sufficient pH range. Therefore, there is a good reason to mix 1: 2 as in the above example.

Further, the relationship between the concentration of hypochlorous acid in the produced strongly acidic water and the ultraviolet absorbance at 292 nm when the strongly acidic water was diluted with strongly alkaline water was examined. FIG. 9 shows that the mixing ratio between the strongly acidic water and the strongly alkaline water is 1: 1:
It is the measurement result of the light absorbency in wavelength 292nm when changing from 1 to 1: 3. The measured value of the absorbance is a value obtained by subtracting the absorbance at 400 nm or more from the absorbance at the wavelength of 292 nm as in the example of FIG.

The measured absorbance difference for some of the mixing ratios and the absorbance corrected for the dilution factor are:
The result is shown in the following table. In other words, when strongly alkaline water is mixed with strongly alkaline water, dissociation into hypochlorite ions proceeds, but the apparent concentration decreases because it is diluted at the same time, so this is corrected with a correction factor corresponding to the dilution factor. There is a need. Mixing ratio Absorbance difference (mAbs) Dilution magnification correction factor Absorbance after correction ----------------------------------- ----------------------------------- 1: 1.5 69.5 (1 + 1.5) / 1 = 2.5 174 1: 2 57.5 (1 + 2) / 1 = 3 173 1: 3 43.0 (1 + 3) / 1 = 4 172

According to the results shown in this table, the absorbance after the correction was 173 ± 1 mAbs, indicating a very good agreement. This table shows that at a mixing ratio of 1: 1.5, all hypochlorous acid has already been dissociated into hypochlorite ions, and when the mixing ratio further increases, simple dilution with strong alkaline water is performed thereafter. Just indicates that the number of hypochlorite ions is substantially constant. In other words, if strong alkaline water is mixed at a pH higher than the pH at which the dissociation of hypochlorous acid to hypochlorite ions will be completely performed, the measurement result should be multiplied by the correction factor corresponding to the mixing ratio. The correct absorbance in proportion to the amount of hypochlorite ions is obtained, and the concentration of hypochlorite ions is eventually known, and finally, the hypochlorous acid in the generated strong acid water before mixing with strong alkaline water The concentration can be determined accurately.

It should be noted that these measurement results and numerical values are obtained under specific conditions, and are not limited thereto. The mixing ratio of 1: 1.5 or 1: 2 is a significant value in the above description, but this is for one example in which tap water to which NaCl was added as an electrolysis aid was used as raw water. It may vary depending on the use of KCl or the like as the agent, the use of well water, or the electrolysis conditions.

In the above description, the absorption at a wavelength of 292 nm of the characteristic absorption peak of hypochlorite ion and almost no absorption were observed.
The difference between these values is measured by measuring the absorbance of not less than 00 nm, and the measurement can be performed with less error. That is, using such a difference absorption method,
The effect of an increase in the background level of absorbance, such as when the mixture is slightly suspended, fine bubbles are generated, or when the flow cell 31 is contaminated, can be eliminated. However, this point can be omitted when the application does not require a very accurate measurement, and the wavelength 292n
It is sufficient to measure only the absorbance at m. If only one wavelength is measured, only one measuring optical system is required, and there is an advantage that the configuration can be simplified and the device can be manufactured at low cost.

Conversely, the accuracy can be further improved by measuring three wavelengths than by measuring two wavelengths. In this case, the measuring optical system for measuring the light transmitted through the flow cell 31 shown in FIG. 1 is changed as follows. In addition to the measurement system of 292 nm wavelength composed of the optical filter 34 and the photocell 36 which pass light near the wavelength of 292 nm and the measurement system of 400 nm wavelength composed of the optical filter 35 and the photocell 37 which pass light of wavelength 400 nm or more, the wavelength An optical filter and a photocell that allow light having a wavelength of about 240 nm to pass through are prepared, and light is guided by a beam splitter added to the optical filter, and light having a wavelength of 240 nm is measured.

Assuming that the measured value A3 is obtained for the light having the wavelength of 240 nm, A3 is a value indicating the absorbance in the wavelength region at the bottom of the absorption spectrum in FIG. That is, the absorbance A1 at a wavelength of 400 nm or more,
This means that in addition to the absorbance A2 at the absorption peak wavelength of 292 nm, the absorbance A3 at the bottom near the wavelength of 240 nm was obtained. The following operation is performed from these values. A4 = A2-{(400-292) A3 + (292-240) A1} / (400-240) = A2- (108.A3 + 52.A1) /160=A2-0.68.A3-0.33.A1 The value A4 is obtained by more accurately removing the background value from the measured absorbance value A2 at a wavelength of 292 nm.

Further, the absorbance to be measured is not limited to the wavelength of 292 nm, and if it is desired that the sensitivity is somewhat sacrificed, the absorbance in the wavelength range of about 260 nm to 330 nm may be detected.

In the above description, the absorbance near the wavelength of 292 nm is corrected by the dilution factor, but the following correction factor may be further added. As can be seen by comparing the curves of FIG. 5 and FIG. 7, the shapes of the absorption spectrum of the mixed solution of the electrolyzed water and the absorption spectrum of the aqueous solution of sodium hypochlorite are slightly different, and the wavelength is 230 to 240 nm.
There is a difference in the cut amount at the nearby bottom peak. This difference is caused by the fact that in the case of electrolyzed water, trace amounts of contaminants are present because NaCl (usually a commercially available product) is added to tap water for electrolysis, while such an aqueous solution of sodium hypochlorite has The present inventors have noticed that this is caused by the fact that no foreign matter is present.

Therefore, by introducing a correction factor for correcting the influence of the above-mentioned minute contaminants in addition to the dilution factor correction factor, more accurate measurement becomes possible. This involves multiplying by a constant coefficient K2 (eg, 0.95), or by a constant value A ', as in one of the following two equations:
(For example, 10 mAbs) may be subtracted. B = (A4−A ′) · K1 · ε where B is the hypochlorous acid concentration, and A4 is the value obtained by the above two-wavelength method (wavelength 400 nm from the value of 292 nm). Is subtracted) or a value obtained by the three-wavelength method (see the above formula), K1 is a dilution factor correction factor, and ε is a molar extinction coefficient.

In addition, the specific configuration and the like can be variously changed without departing from the spirit of the present invention. For example, in the above description, the number of tubes for guiding the strongly acidic water and the strongly alkaline water for measurement is one, but a plurality of tubes such as two on the strongly acidic water side and three on the strongly alkaline water side may be used. Also, the inner diameter of the tube is not the same, and those having different diameters can be used.

Although the ironing pumps 73, 74, and 75 were used as the liquid supply system for these liquids in the above, an air pump,
Other suction devices such as aspirators, diaphragm valves, etc. can be used. 10 and 11 as the liquid sending system.
, A gravity method, a siphon method, and the like. In the gravity method of FIG. 10, a supply port 79 is provided on the bottom surface of the individual liquid tank 62 (or 63) of the first liquid tank 61, and a tube 64 (or 65) is attached thereto. According to the liquid level height h determined by the position of the outlet,
The liquid flows out of the supply port 79 at a constant flow rate, and the liquid can be sent at a constant flow rate. The supply port 79 is preferably tapered as shown in the figure. In the siphon system of FIG.
The height of the tip of the tube 64 (65) and the liquid tank 62 (6
The liquid can be sent at a constant flow rate according to the difference H with the liquid level in 3). In this siphon system, the liquid tank 62 (6
The liquid remains stored in the tube 64 (65) up to the height of the outlet of the tube 64 (65) in 3), so that when the next use is started, the liquid can be smoothly fed.

Various types of filters can be used as the optical filters 34 and 35. For example, an interference filter having a main transmission wavelength of 400 nm may be used as the optical filter 35, or a band-pass filter (for example, HOYA) B-430 glass filter) or a sharp cut-off filter (for example, HOYA L-42). Further, the photocells 36 and 37 are not limited to the Si photocell, and other equivalent photoelectric converters such as a photomultiplier, a phototube, and a CdS cell can be used. Further, by combining the optical filter and the detector, a monochromator using a grating and C
It can be replaced with a combination of a line sensor such as a CD or PDA.

Further, an operation panel 85 as shown in FIG. 12 can be provided in the housing 76 of the measuring section 30. The operation panel 85 includes a power switch 86 for turning on / off the entire power supply, a mode switch 87 for switching the measurement mode between a normal mode and a blank mode, and a display indicating an operation state (for example, an LED display). ) 88 are provided.

The normal measurement mode is a measurement mode when the electrolysis is turned on as described above. The blank measurement mode is a measurement mode when the electrolysis is turned off, and the electrolysis tank 1 of the electrolyzed water generation unit 10
Disconnecting the DC voltage source 14 from the two electrodes 12 and 13 provided in 1 so that electrolysis does not occur;
In addition, the measurement is performed with the liquid supply pump 83 from the salt water tank 82 turned off. That is, when the switch 87 is turned to the blank side, the control circuit formed on the main board 78 controls the DC voltage source 14 to be turned off and also turns off the liquid feed pump 83.

Also in this blank mode, as in the normal mode, water guided from the outlets 17 and 18 from both sides of the electrodes 12 and 13 of the electrolytic cell 11 respectively is a two-tank type open-to-air first liquid tank. After being introduced into each of the two tanks 62 and 63 of 61, it is led to the second liquid tank 67 of the open-to-atmosphere type by the ironing pumps 73 and 74, where it is stirred and mixed, and then guided to the measuring unit 30 by the ironing pump 75. Wavelength 2
The absorbance at 92 nm and the wavelength of 400 nm (or the absorbance near the wavelength of 240 nm in addition thereto) is measured. In this case, since the electrolysis has stopped, the electrode 1
The water coming out from the outlets 17 and 18 on both sides of the tanks 2 and 13 is the tap water itself supplied to the tank 11, and is mixed in the second liquid tank 67 and sent to the measuring unit 30. Is the tap water itself. Therefore, it is possible to obtain the absorbance measurement value (blank value) of the tap water itself in which no electrolysis is performed.

The blank value indicates the hypochlorous acid concentration measured for tap water, that is, an offset value of a measured value generated depending on water quality or the like. This offset value fluctuates due to water quality fluctuation and the like. The light absorption intensity of water (tap water) itself, which is a raw material for electrolysis, not only varies from region to region, but also varies insignificantly depending on the season and weather (so-called water quality change). Especially after rain, the turbidity of water quality is reflected, and an apparent increase in concentration is observed. So, this apparent measurement value (offset value)
Is stored in the memory of the control circuit in the main board 78, and the measured value in the normal mode is corrected. The measured value of the absorbance at a wavelength of 400 nm or more in the blank mode is A'1, the measured value of the absorbance at an absorption peak wavelength of 292 nm is A'2 (and the measured value of the absorbance at a wavelength around 240 nm is A'3). Then, the measured values A1, A2 (and A3) in the normal mode are (A1−A′1),
(A2-A'2) (and (A3-A'3)).

Normally, this offset value is merely measured at the time of installation of the apparatus, and only corrects the measured value obtained in the normal mode. However, since there is a seasonal variation as described above, a mode changeover switch 87 is provided to arbitrarily set the offset value. The blank value is measured so that the offset value can be correctly corrected without being affected by seasonal variations. Specifically, with the power switch 86 turned on, the mode changeover switch 87 is tilted to the blank side to set the blank measurement mode. Then, the display 88 switches from the display during the generation of the electrolytic water to the display during the blank correction. Switching to the blank mode can be performed at an arbitrary timing. For example, if the switching is performed once a week, most of the fluctuations can be handled.

When the mode changeover switch 87 is turned to the blank side, the DC voltage source 14 and the liquid feed pump 83 are turned off, so that simple tap water is introduced into the electrolytic cell 11. If the electrolysis was performed before that, the strong acid water and the strong alkaline water generated by the electrolysis were gradually replaced with simple tap water, and about 15 minutes had passed since it was dropped to the blank side Then, the measuring unit 3
The water sent to zero is completely replaced by simple tap water. When the blank reading is stable enough,
An instruction is issued from the control circuit to store the measurement in a memory, which is stored. Thereafter, when the mode changeover switch 87 is returned to the normal state, the DC voltage source 14 is turned on again, the liquid sending pump 83 is turned on, and water in which sodium chloride is mixed with tap water is sent to the electrolytic cell 11. Then, a normal measurement is performed on the strongly acidic water generated by the electrolysis. Then, the correction for the normal measured value is performed using the stored blank value. In the normal mode, the polarity of the DC voltage applied to each of the electrodes 12 and 13 is alternately inverted periodically (every about 20 minutes) to protect the electrodes 12 and 13. When this polarity reversal is being performed, the display 88 indicates “electrode switching”.

After the blank value is stored in the memory, the power can be automatically turned off and reset once, or the power can be returned to the normal state while the power is on. You can also.
As the changeover switch 87, a momentary type or an alternate type can be used. When a momentary changeover switch 87 is used, it is desirable that the switch is apparently held in a blank mode via a relay. By doing so, it is possible to prevent an erroneous operation in which tap water is supplied as it is intended for normal use when the power is turned on next time.

[0060]

As described above, according to the apparatus for producing electrolyzed water of the present invention, strong alkaline water generated on the cathode side is used and mixed with strong acidic water generated on the anode side. Is measuring hypochlorous acid concentration in strongly acidic water at
It is not necessary to add a coloring reagent by a colorimetric method or the like, and the concentration of hypochlorous acid in strong acidic water can be reduced without the need for maintenance such as replacement and replenishment of the coloring reagent and without wasting space for them. It is possible to monitor every moment. The strongly acidic water and the strongly alkaline water are introduced into a two-stage open-to-atmosphere type liquid tank to disperse bubbles, and the strongly acidic water and the strongly alkaline water are sufficiently mixed by forcibly stirring in the second liquid tank. In addition, each of the liquid sending means for sending the strongly acidic water and the strong alkaline water to the second liquid tank and the liquid sending means for sending the mixed solution are independent, and the flow resistance and the like are changed. Since the mixing ratio can be kept constant by adjusting the flow rate accordingly, the measurement accuracy of the concentration of hypochlorous acid in the strongly acidic water can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a specific embodiment.

FIG. 3 is a graph showing a light absorption spectrum of strongly acidic water generated on the anode side.

FIG. 4 is a graph showing an absorption spectrum of light of strongly alkaline water generated on the cathode side.

FIG. 5 shows that the generated strongly acidic water and strongly alkaline water are mixed at a ratio of 1: 2.
4 is a graph showing a light absorption spectrum of mixed water mixed in FIG.

FIG. 6 is a graph showing the ratio of free chlorine to pH.

FIG. 7 is a graph showing a light absorption spectrum of an aqueous antiformin solution.

FIG. 8 is a graph showing the relationship between the mixing ratio of strongly acidic water: strongly alkaline water and pH.

FIG. 9: Mixing ratio of strongly acidic water: strongly alkaline water and wavelength 292
The graph showing the relationship with the absorbance in nm.

FIG. 10 is a schematic cross-sectional view showing another example of the liquid feeding system.

FIG. 11 is a schematic cross-sectional view showing still another example of the liquid feeding system.

FIG. 12 is a schematic view illustrating an example of an operation panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electrolyzed water generator 11 Electrolyzer 12 Anode 13 Cathode 14 DC voltage source 15 Diaphragm 16, 21, 22 Valve 17 Strong acid water outlet 18 Strong alkaline water outlet 30 Measuring unit 31 Flow cell 32 Light source 33 Beam splitter 34, 35 Optical Filter 36, 37 Photocell 60 Mixing unit 61 First liquid tank 62, 63 Individual liquid tank 64, 65, 68 Suction tube 67 Second liquid tank 69 Filter 71 Stirrer 72 Stirring motor 73, 74, 75 Ironing pump 76 Housing 77 Measuring section cover 78 Measuring section main board 79 Supply port on bottom of liquid tank 81 Softener 82 Salt water tank 83 Liquid feed pump 84 Mixer 85 Operation panel 86 Power switch 87 Mode switch 87 Mode display

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G059 AA05 BB04 CC20 DD05 EE01 EE12 FF06 GG10 HH03 HH06 JJ02 JJ03 JJ22 KK03 MM01 PP04 4C058 AA12 AA21 BB02 BB07 DD01 DD03 DD13 EE26 JJ07 4D061 EB03 FA11 FA20 GA11 GA20 GA21

Claims (2)

[Claims] 1. An electrolytic cell comprising two electrodes, capable of electrolyzing chlorine-containing water by applying a positive or negative voltage to each electrode, and water respectively guided from both electrode sides. Two tank type first introduced into each separated tank
An open-to-atmosphere type liquid tank, and first and second liquid sending means for independently sending water from each tank of the first open-to-atmosphere type liquid tank,
A second air-opening liquid tank for storing the fed water and mixing them by forcible stirring, and a second air-feeding liquid mixture in the second air-opening liquid tank at a predetermined flow rate. And a measuring means for measuring the light absorption intensity of the mixed liquid sent by the third liquid sending means substantially in a wavelength range of 260 nm to 330 nm. Electrolyzed water production equipment. 2. The apparatus for producing electrolyzed water according to claim 1, further comprising means for arbitrarily stopping electrolysis by not applying a voltage to each electrode in the electrolytic cell,
Means for correcting the measured value of light absorption intensity when electrolysis is performed in the electrolytic cell, based on the measured value of light absorption intensity measured by the measuring means when the electrolysis is stopped. Electrolyzed water production equipment.